I would not use that Flyback! It can arc high voltage out of the crack and hit sensitive electronics near by, not to mention your hand if you are trying to service anything.
I have close to 20 CRT's in the garage, like MAC's they can become a bad habit, and I know for a fact that that is the death of most CRT's.
Be very careful and if I were you I would be trying to source a replacement or an entire analog board to replace this one.
Sorry this happened!